WASHINGTON - Two years after the U.S. invasion of Iraq, the Pentagon has formally included in key strategic plans provisions for launching preemptive strikes against nations thought to pose a threat to the United States.

The doctrine also now stipulates that the U.S. will use "active deterrence" in concert with its allies "if we can" but could act unilaterally otherwise, Defense officials said.

The changes codify the more assertive defense policy adopted by the Bush administration since the Sept. 11 attacks and are included in a "National Military Strategy" and "National Defense Strategy," reports that are part of a comprehensive review of military strategy conducted every four years.

"The president has the obligation to protect the country," said Douglas J. Feith, the Defense Department's undersecretary for policy. "And I don't think that there's anything in our Constitution that says that the president should not protect the country unless he gets some non-American's participation or approval of that."

Pentagon managers use the strategic plan to guide such decisions as where to place bases, which bases to eliminate, what weapons to buy and where to position them. The heads of the United States' regional commands across the globe, in turn, use the strategy to prioritize spending and form strategies for eliminating threats in their regions.

"The potentially catastrophic impact of an attack against the United States, its allies and its interests may necessitate actions in self-defense to preempt adversaries before they can attack," the National Military Strategy states. A previous version, compiled in 1997, did not include plans for preemptive attacks.

However, Feith said that the United States would for the first time invite close allies such as the United Kingdom to review classified portions of U.S. defense strategy as part of the Quadrennial Defense Review, a four-year military policy and spending plan.

But the new strategy document further shifts the nation from the Cold War strategy of containing Eastern Europe to a global strategy of taking on enemies that emerge unexpectedly - as the administration argues Afghanistan did after the Sept. 11 attacks - and even terrorist organizations within friendly nations.

It appears to move the nation further from reliance on such international coalitions as NATO and more toward what Defense Secretary Donald H. Rumsfeld has called "coalitions of the willing" under clear American leadership, analysts said.

"NATO is kind of missing in action now in their strategy," said Loren Thompson, a military analyst with the Lexington Institute, a public policy group in Arlington, Va. "During the Clinton years coalition warfare with the other members of NATO was a centerpiece to our strategy, and now the administration is expecting almost nothing from the Europeans."

In some cases, respected global organizations seem to be viewed with suspicion. In describing the vulnerabilities of the United States, the document uses strong language to list international bodies - such as the International Court of Justice, created under a treaty that the United States has declined to sign - alongside terrorists.

"Our strength as a nation-state will continue to be challenged by those who employ a strategy of the weak using international [forums], judicial processes and terrorism," the document states.

The concern, Feith explained, was that some nations would try to criminalize American foreign policy by challenging it in international courts.

During the Cold War, the United States used the United Nations and the North Atlantic Treaty Alliance in an effort to build world consensus against anticipated threats from the Chinese and the now dissolved Soviet bloc. The new strategy highlights the United States' increasing inability to predict where the next conflict will occur, Feith said.

"I don't think that the world gives us the luxury of picking areas," Feith said. "We have interests all over the world. I dare say that if anybody before September 11, 2001, was listing places that we would want to focus on as a matter of priority, Afghanistan would have been rather low on the list."